Plastic-derived mesophasic carbon

Abstract

Methods and systems for producing mesophasic (between liquid and solid phases) carbon materials from plastic waste. The method and system includes a 2-stage pyrolysis reactor, including first and second pyrolysis stages where a carbon feedstock material is subjected to pyrolysis. The first pyrolysis stage may subject the carbon feedstock material to pyrolysis at a first temperature in a range of 500° C. to 700° C., and the second pyrolysis stage may operate at a second temperature in a range of 800° C. to 1000° C., providing secondary gas phase reactions (SGR). A residence time of the carbon feedstock material in the reactor may be no more than 10 seconds. After pyrolysis and SGR, a sparging and thermal treatment stage may convert pyrolysis tar products to an anisotropic pitch product suitable for use in production of carbon fiber or bulk graphite for use in fabrication of graphite electrodes.

What is claimed is: 
     
         1 . A method for producing mesophasic carbon material, the method comprising:
 subjecting a carbon feedstock material to pyrolysis within a 2-stage pyrolysis reactor including a first pyrolysis stage and a second pyrolysis stage, wherein the carbon feedstock material comprises a plastic material;   wherein the first pyrolysis stage subjects the carbon feedstock material to pyrolysis gas phase reactions at a first temperature and the second pyrolysis stage operates at a second temperature that is higher than the first temperature; and   subjecting pyrolysis products from the 2-stage pyrolysis reactor to a sparging and thermal treatment stage, in which the pyrolysis products from the 2-stage pyrolysis reactor are converted from pyrolysis tar products to an anisotropic pitch product suitable for use in production of carbon fiber or bulk graphite for use in fabrication of graphite electrodes.   
     
     
         2 . The method of  claim 1 , wherein the plastic material is a waste plastic material. 
     
     
         3 . The method of  claim 2 , wherein the waste plastic material comprises at least one of polystyrene, polyethylene, or polypropylene. 
     
     
         4 . The method of  claim 1 , wherein the first and second pyrolysis stages, and/or the sparging and thermal treatment stage are conducted under an inert atmosphere. 
     
     
         5 . The method of  claim 1 , wherein the first pyrolysis stage has a temperature of from 500° C. to 700° C. 
     
     
         6 . The method of  claim 1 , wherein the first pyrolysis stage operates at a temperature of about 600° C. 
     
     
         7 . The method of  claim 1 , wherein the second pyrolysis stage has a temperature of from 800° C. to 1000° C. 
     
     
         8 . The method of  claim 1 , wherein the second pyrolysis stage operates at a temperature of about 900° C. 
     
     
         9 . The method of  claim 1 , wherein the anisotropic pitch product has an OTI of at least 10 on a scale of 0-40. 
     
     
         10 . The method of  claim 1 , wherein the anisotropic pitch product has an OTI of at least 20 on a scale of 0-40. 
     
     
         11 . The method of  claim 1 , wherein the anisotropic pitch product has an OTI of at least 30 on a scale of 0-40. 
     
     
         12 . The method of  claim 1 , wherein the carbon feedstock material comprises at least 5% plastic waste material. 
     
     
         13 . The method of  claim 1 , wherein the carbon feedstock material comprises at least 10% plastic waste material. 
     
     
         14 . The method of  claim 1 , wherein the carbon feedstock material comprises at least 20% plastic waste material. 
     
     
         15 . The method of  claim 1 , wherein the carbon feedstock material comprises both plastic waste material and coal. 
     
     
         16 . The method of  claim 1 , wherein a residence time of the carbon feedstock material in the 2-stage pyrolysis reactor, or within the second pyrolysis stage of the 2-stage pyrolysis reactor is no more than 10 seconds. 
     
     
         17 . The method of  claim 1 , wherein a residence time of the carbon feedstock material in the second stage of the 2-stage pyrolysis reactor is no more than 5 seconds. 
     
     
         18 . The method of  claim 1 , further comprising condensing the pyrolysis products from the second pyrolysis stage before subjecting the pyrolysis products from the 2-stage pyrolysis reactor to a sparging and thermal treatment stage. 
     
     
         19 . A method for producing mesophasic carbon material, the method comprising:
 subjecting a carbon feedstock material to pyrolysis within a 2-stage pyrolysis reactor, the 2-stage pyrolysis reactor including a first pyrolysis stage and a second pyrolysis stage, wherein the carbon feedstock material comprises a waste plastic material;   wherein the first pyrolysis stage subjects the carbon feedstock material to pyrolysis at a first temperature in a range of 500° C. to 700° C., and the second pyrolysis stage subjects material exiting from the first pyrolysis stage to secondary gas phase reactions, at a second temperature in a range of 800° C. to 1000° C., wherein a residence time of the carbon feedstock material in the second stage of the 2-stage pyrolysis reactor is no more than 10 seconds; and   subjecting pyrolysis products from the 2-stage pyrolysis reactor to a sparging and thermal treatment stage, in which the pyrolysis products from the 2-stage pyrolysis reactor are converted from pyrolysis tar products to an anisotropic pitch product suitable for use in production of carbon fiber or bulk graphite for use in fabrication of graphite electrodes.   
     
     
         20 . A system for producing anisotropic, mesophasic carbon material from waste plastic, the system comprising:
 a 2-stage pyrolysis reactor configured to subject a carbon feedstock material to pyrolysis, the 2-stage pyrolysis reactor including a first pyrolysis stage and a second pyrolysis stage, wherein the carbon feedstock material comprises a plastic waste material;   wherein the first pyrolysis stage subjects the carbon feedstock material to pyrolysis gas phase reactions at a first temperature in a range of 500° C. to 700° C., and the second pyrolysis stage operates at a second temperature in a range of 800° C. to 1000° C., wherein a residence time of the carbon feedstock material in the 2-stage pyrolysis reactor, or in the second pyrolysis stage of the 2-stage pyrolysis reactor is no more than 10 seconds; and   a sparging and thermal treatment stage, in which condensed pyrolysis products from the second pyrolysis stage are converted from pyrolysis tar products to an anisotropic pitch product suitable for use in production of carbon fiber or bulk graphite for use in fabrication of graphite electrodes.